Why are you not putting a CertPrincipalName? Poweshell is reading your "none" exactly as you type it, which is a string. If you want it blank you have to put "CertPrincipalName:$null" or "CertPrincipalName:none" (that tricky colon). Plus CertPrincipalName is an optional perameter for the set-outlookprovider cmdlet. DJ Grijalva | MCITP: EMA 2007/2010 SPA 2010 | www.persistentcerebro.com

Duplicated problem with http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/75d5dc70-c869-4f76-aa45-640d4e85985a Thanks for your update and confimation. Have a nice day :) Fiona Liao TechNet Community Support

Why are you not putting a CertPrincipalName? Poweshell is reading your "none" exactly as you type it, which is a string. If you want it blank you have to put "CertPrincipalName:$null" or "CertPrincipalName:none" (that tricky colon). Plus CertPrincipalName is an optional perameter for the set-outlookprovider cmdlet. DJ Grijalva | MCITP: EMA 2007/2010 SPA 2010 | www.persistentcerebro.com Nope. I don't think Outlook reads "none" as string. As you can see in my first screen shot, it reads 'none' as to disable the mutual authentication. $null and none are different. $null means to take external host name as the cert principal name. I suspect it's a bug of Outlook since its behavior is inconsistent.

Hi, there, A strange behavior of Outlook Anywhere. Environment: Exchange 2010 SP2, Outlook 2010 ver 14.0.4760.1000 (32-bit)My users have been using Outlook Anywhere for a few months, no problemRecently, for some reason, I need to disable OA mutual authenticationI run this command on Exchange server: Set-OutlookProvider EXPR -CertPrincipalName none Now I create a new Outlook profile on my PC. Everything works fine, I got what I want: But, what happens to my old (existing) Outlook profile? When I launch Outlook using old profile, it keeps prompting for password. When I open the old profile, I see this, Instead of disabling the mutual authentication, it uses the string 'none' as the cert principal name. Has anyone encountered the same issue?

Confirmed it's a bug of Outlook 2010 RTM. I applied SP1 and the symptom is gone. Mutual authentication has been disabled for existing Outlook profile.